Increasing the effectiveness and adoption of agricultural phosphorus management strategies to minimize water quality impairment

Authors: OSMOND, DEANNA - North Carolina State University; SHOBER, AMY - University Of Delaware; SHARPLEY, ANDREW - University Of Arkansas; Duncan, Emily; HOAG, D - Colorado State University

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/25/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary: Phosphorus is a critical nutrient for agricultural production, but can also contribute to water quality problems in the United States and around the globe. This journal article seeks to provide an overview of the status of management practices and their impact on phosphorus, in addition to determining how the scientific community can increase the effectiveness and adoption of these best management practices. The bottom line is that changes must occur at the watershed scale and in intentional and transparent fashion.

Technical Abstract: Phosphorus (P) is essential for optimum agricultural production but also causes water quality degradation when lost through erosion (sediment-attached P), runoff (soluble reactive P-SRP), or leaching (sediment-attached P or soluble reactive P). Implementation of conservation practices affect P at the source (avoiding), during transport (controlling), or at the water resource edge (trapping). Tradeoffs often occur with conservation practice implementation. For instance, multiple researchers have shown that conservation tillage reduces total P by over 50%, while increasing SRP by upwards of 40%. As SRP is more bioavailable, conservation tillage may increase water quality degradation. Conservation practices must be implemented as a system of practices to increase redundancy and to address all loss pathways, for example P management, conservation tillage, and riparian buffer. Further, planning and adoption must be at a watershed scale to ensure practices are placed in critical source areas, thereby providing the most treatment for the least price. Farmers must be involved in watershed planning that include financial backstopping and educational outreach. It is imperative that conservation practices be used more effectively to reduce and retard off-site P losses. New and innovative conservation practices are needed to improve control of P leaching, address legacy stores of STP, and mitigate increased P losses expected with climate change. Without immediate changes to conservation practice implementation, P losses will increase due to climate change with the concomitant degradation of water quality. These changes must be done at a watershed scale in an intentional and transparent manner.